1. Technical Field
The present invention relates to a method of manufacturing an electronic device and an electronic device.
2. Related Art
A lead frame is used as a metal plate which supports an IC (Integrated Circuit) element inside an electronic device and leads a plurality of terminals of the semiconductor element to the outside of a resin package.
FIGS. 24A to 25B are process views showing a method of manufacturing an electronic device according to the related art. FIGS. 24A to 25A are plan views, and FIG. 25B is a sectional view taken along the arrow of FIG. 25A. In FIG. 25A, to avoid complexity of the drawing, an upper mold 141 (see FIG. 25B) is not shown.
As shown in FIG. 24A, first, a lead frame 110 is prepared. The lead frame 110 has a die pad 111 for fixing an electronic part, a plurality of leads 112 for leading the respective terminals of an electronic part fixed onto the die pad 111 to the outside, and a dam bar 113 for connecting a plurality of leads 112. The dam bar 113 has a frame shape conforming to the outer edge of the resin package in plan view. The dam bar 113 prevents mold resin from spreading outside the frame when the electronic part is sealed with resin. In the lead frame 110, the die pad 111, a plurality of leads 112, and the dam bar 113 are formed integrally of a single copper plate.
Next, as shown in FIG. 24B, an electronic part 121 is attached onto the die pad 111 of the lead frame 110. The respective terminals of the electronic part 121 and the leads 112 are connected to each other by using, for example, gold wires 131 or the like. Next, as shown in FIGS. 25A and 25B, the electronic part 121 fixed onto the die pad 111 is arranged between an upper mold 141 and a lower mold 142, and both molds are clamped so as to sandwich the dam bar 113 therebetween from above and below, so that a cavity 143 is formed. The mold resin is injected into the cavity 143 and hardened. Thus, a resin package is formed, and the electronic part 121 is sealed in the resin package. Thereafter, the cavity 143 is opened, the resin package is extracted, and the dam bar 113 outside the resin package is cut to respectively separate a plurality of leads 112. In such a manner, an electronic device is completed.
Other examples of the related art are JP-A-7-231069 and JP-A-8-31998.
That is, JP-A-7-231069 describes a method which divides a stage portion, on which an electronic part is mounted, into a plurality of areas, and, for example, respectively uses first to third areas as an element mounting area, a ground layer, and a power supply layer. According to the method described in JP-A-7-231069, a stage-portion frame having the first to third areas and a lead-portion frame having a predetermined number of leads are provided separately and arranged to overlap each other.
JP-A-8-31998 describes a structure in which a pair of leads in a sealed body (package) are bent halfway and extend obliquely upward, a semiconductor chip is fixed at the lower surface of one lead extending obliquely upward, one end of a wire is connected to the lower surface of the other lead, and the other end of the wire is connected to an electrode of the semiconductor chip.
According to the related art shown in FIGS. 24A to 25B, for example, as shown in FIG. 26A, when two electronic parts 121 and 122 are arranged in one resin package, the two electronic parts 121 and 122 may be arranged in parallel on the die pad 111. However, as shown in FIG. 26B, when the electronic parts 121 and 122 are larger than the die pad 111, portions of the electronic parts 121 and 122 overlap each other in plan view and come into contact with each other (that is, interfere with each other).
To avoid such a situation, according to the related art, it is necessary to increase the area of the die pad 111 in accordance with the number of electronic parts 121 and 122 or the size of the electronic parts 121 and 122, resulting in a significant increase in the size of the resin package.
The technique described in JP-A-7-231069 cannot eliminate such a problem. In addition, JP-A-8-31998 has not supposed that a plurality of electronic devices are arranged in a single resin package.